Crohn’s & Ulcerative Colitis: Know the Difference

Written by Carlie Olenick
Medically Reviewed by Melinda Ratini, MS, DO on July 08, 2025
9 min read

You’ve had stomach cramps for weeks. You’re exhausted and losing weight. And you keep having to run to the bathroom. What’s going on? 

Your doctor may suspect an inflammatory bowel disease (IBD). But which one?

There are two common types, Crohn’s disease and ulcerative colitis. They have a lot in common, like long-term inflammation in your digestive tract. But the conditions also have some key differences. And that can mean one treatment may work better for your Crohn's disease but not for ulcerative colitis.

By the way, if you hear some people just say “colitis,” that means inflammation of your colon. But with “ulcerative colitis,” you also have sores (ulcers) in the lining of your colon. Find out how ulcerative colitis and Crohn's disease are different and which treatments best help your condition.

Crohn’s disease and ulcerative colitis (UC) symptoms can sometimes look alike. The conditions are two different medical conditions.

But both Crohn's disease and ulcerative colitis can cause you to get:

  • Belly cramps and pain
  • Diarrhea
  • Constipation
  • An urgent need to have a bowel movement
  • A feeling like your bowel movement wasn’t complete
  • Rectal bleeding
  • Iron deficiency, such as anemia
  • Fever
  • Smaller appetite
  • Weight loss
  • Fatigue
  • Night sweats
  • Problems with your period, such as irregular or skipped periods

You might not have all of these symptoms all the time. They may come and go. Your condition may switch between flares (symptoms getting worse) and remission (symptoms easing up or stopping).

Crohn’s and ulcerative colitis are most often diagnosed in teenagers and young adults. But you can get diagnosed at any age. And these conditions tend to run in families.

There are three key differences:

Location. Ulcerative colitis only affects your colon and rectum (parts of the large intestine). Though not as common, some people have pancolitis, a type of UC that can impact the whole colon. 

But Crohn’s disease can inflame any part of your digestive tract — from your mouth to the anus. Crohn’s usually affects your:

  • Small intestine
  • Large intestine
  • Junction where the small and large intestines meet (terminal ileum)
  • Mouth, causing sores between your gums and lower lip or along the sides or bottom of your tongue
  • Anus, causing tears (fissures), ulcers, infections, or narrowing

Pattern of inflammation (continuous areas or not). People with Crohn’s disease often have healthy areas in between inflamed spots. But with ulcerative colitis, the inflamed spots stay together.

Layers affected. Crohn’s often spreads down into deeper layers of your intestines. But ulcerative colitis stay in the innermost lining of your colon.

Are risk factors the same for Crohn’s and UC?

Some risk factors are the same for Crohn’s and UC, but some are not. For instance, a diet high in total fat is linked to higher risk for Crohn’s and UC. But some factors can raise your risk for Crohn’s but not ulcerative colitis. 

You may have a high risk for Crohn’s if you:

  • Smoke
  • Don’t exercise regularly
  • Don’t eat a high-fiber diet
  • Have vitamin D deficiency

But smoking, physical activity, and diet don’t seem to affect your risk for ulcerative colitis.

To get the right diagnosis, your doctor will run blood tests and imaging scans. They’ll check your blood for signs of infection, low red blood cells (anemia), and more. Your doctor may also take a stool sample. This can help test for infection and bleeding in your intestines.

But the differences mostly revolve around where your digestive system is inflamed. The best way to tell UC from Crohn’s is to take a look inside your colon.

X-rays can show places where your intestine is blocked or unusually narrow.

Contrast X-rays have you swallow a thick, chalky, barium liquid so your doctor can see how it moves through your digestive system.

CT scans and MRIs can give a detailed image of your entire intestines and nearby tissues. These scans can also help your doctor see how much of the intestine is inflamed or if there are any complications.

Endoscopy uses a tiny camera on a thin tube to view your digestive system. 

Here are some specific types of endoscopy:

  • Sigmoidoscopy looks at the lower part of your large intestine.
  • Colonoscopy looks at your entire large intestine. 
  • An esophagogastroduodenoscopy (EGD) checks the lining of your esophagus, stomach, and duodenum.
  • A pill, or capsule, endoscopy uses a pill-sized camera to look at your small intestine.
  • An endoscopic retrograde cholangiopancreatography (ERCP) can see your bile and pancreatic ducts.

Sometimes, even after all the tests are completed, your doctor can’t tell which condition you have. That’s true for 1 in 10 people with IBD. That’s because you may have signs of both conditions. 

Your doctor may diagnose you with “indeterminate colitis.” This means it’s not clear which type of inflammation you have.

Because both conditions are similar, many treatments also overlap. Here are some ways to treat Crohn’s and UC.

Lifestyle changes. These include making changes to the diet, exercising regularly, quitting smoking, and avoiding pain meds called “NSAIDs” (nonsteroidal anti-inflammatory drugs), such as ibuprofen.

Stress management is also key. Stress doesn’t cause IBD, but it can lead to flare-ups. So try to cut down on the things that make you tense, and find ways to relax. Exercise is a great way to do that. So are other healthy things you might enjoy and find meaningful, such as hobbies, meditation, prayer, volunteering, and positive relationships.

Medicines. Thesecan help you get the inflammation under control. Here are some medications used for Crohn’s and some for UC:

Oral 5-aminosalicylates. Also called“5-ASAs,” these medicines include balsalazide (Colazal), mesalamine (Asacol, Delzicol, Lialda, and Pentasa), olsalazine (Dipentum), and sulfasalazine (Azulfidine). They target the last part of your small intestine and colon. 

And the meds can work to lower inflammation in the lining of your GI tract. They treat your ulcerative colitis flare , maintain treatment, and prevent relapses.

Steroids. Budesonide and prednisone can curb your immune system. These medicines can lower inflammation in IBD. But the meds don’t heal the damage in your intestine. And because of side effects, you likely take them for a short time.

Immune system modifiers. These medicines can dampen your immune system. Medicines such as 6-mercaptopurine (6-MP, Purinethol, Purixan) and azathioprine (Imuran, Azasan) can treat moderate to serious Crohn’s and UC. 

But if other medications aren’t working, your doctor may use:

  • Cyclosporine (Gengraf, Neoral, Sandimmune)
  • Methotrexate (Rheumatrex, Trexall)

Biologics and their biosimilars. These therapies can suppress your immune system to lower inflammation. Your doctor may give them as an injection or by IV (through a vein). And immunotherapy can be combined with other medicines, too. 

Biologics may treat Crohn’s disease or UC. These include:

TNF inhibitors

  • Adalimumab (Humira)
  • Infliximab (Remicade)

Biosimilars to Humira

  • Adalimumab-aacf (Idacio)
  • Adalimumab-aaty (Yuflyma)
  • Adalimumab-abdnm (Cyltezo)
  • Adalimumab-adaz (Hyrimoz)
  • Adalimumab-atto (Amgevita)
  • Adalimumab-aqvh (Yusimry)
  • Adalimumab-bwwd, (Hadlima)
  • Adalimumab-fkjp (Hulio)
  • Adalimumab-ryvk (Simland)

Biosimilars to Remicade

  • Infliximab-abda (Renflexis)
  • Infliximab-axxq (Avsola)
  • Infliximab-dyyb (Inflectra)
  • Infliximab-qbtx (IXIFI) 

Medications to lower inflammatory proteins (Interleukin-12 and interleukin-23)

  • Ustekinumab (Stelara)

Biosimilars to Stelara 

  • Ustekinumab-aauz (Otulfi)
  • Ustekinumab-aekn (Selarsdi)
  • Ustekinumab-auub (Wezlana)
  • Ustekinumab-srlf (Imuldosa),
  • Ustekinumab-ttwe (Pyzchiva)

Other immunotherapies

  • Vedolizumab (Entyvio)
  • Risankizumab-rzaa (Skyrizi)
  • Golimumab (Simponi, Simponi Aria) may also treat IBD
  • Mirikizumab (Omvoh) may also treat IBD
  • Certolizumab pegol (Cimzia) only treats Crohn's disease

With treatment for mild symptoms, almost all (90%) of the UC cases go into remission. But with “refractory” UC, you may need continuous treatment with steroids. 

Complete remission with Crohn’s disease is less common. And some people eventually need surgery. That includes up to 45% of people with UC and 75% of people with Crohn’s.

You and your doctor might talk about surgery if you get:

  • Serious symptoms, and medications aren’t helping
  • A blockage in your digestive tract
  • A tear or hole in the side of your intestine

If you have either condition, your checkups are important. Regular check-ins can help your symptoms start to ease up.

You may also need to get a colonoscopy more often. And your colonoscopy may start at a younger age, too. A colonoscopy can check for cancer or polyps. The procedure helps your doctor remove anything that needs to come out. 

Experts suggest starting these tests within 8-10 years after you develop UC or Crohn’s symptoms. And then typically every one to three years after that. Your doctor will talk to you about a treatment plan. They can help you schedule the best time for you.

When to call the doctor

Some symptoms may need medical treatment. Call your doctor or see a health care professional if you have:

  • Pain in your belly
  • Blood in your poop (stool)
  • Diarrhea that does not go away with medication, wakes you up from sleep, or lasts more than two weeks
  • A fever lasting more than a day
  • Nausea or vomiting
  • Weight loss without trying to

Crohn’s and ulcerative colitis (UC) are types of inflammatory bowel disease (IBD). UC only inflames your large intestine, but Crohn’s can affect any part of your digestive tract. In Crohn’s, you have inflamed spots mixed with clear areas, unlike the continuous inflamed area of UC. Talk to your doctor about getting the right diagnosis early, and lower your risk for complications.

Can colitis turn into Crohn’s?

Ulcerative colitis (UC) doesn’t actually turn into Crohn’s disease, but sometimes it can seem that way. What can happen is you may be diagnosed with UC at first. But as more symptoms show up over time, the diagnosis might change to Crohn’s. 

Crohn’s and UC can look a lot alike, especially in the beginning. So it’s not uncommon for your diagnosis to change. But they are still two different conditions. You can’t have both at the same time. 

What not to eat during Crohn’s?

During a Crohn’s flare-up, it’s important to avoid foods that can irritate your gut. A diet called the Crohn’s disease exclusion diet (CDED) can help. The diet may lower your symptoms and support healing. 

This diet cuts out foods that may negatively affect your gut:

  • Wheat and other gluten-containing grains 
  • Dairy products 
  • Animal fats 
  • Additives and ultra-processed foods 
  • Red meat 

Instead, focus on eating:

  • Whole foods 
  • Fruits
  • Vegetables
  • Rice
  • Potatoes
  • Lean meats and eggs

You can also use a nutritional formula, under the guidance of your health care provider or dietitian. It can help make sure you get enough calories and nutrients. 

What foods should you avoid if you have ulcerative colitis?

Avoid trigger foods that can make your flare-ups worse. “If you have ulcerative colitis (UC), steer clear of ultra-processed foods, such as those containing additives," says Nikhil Kadle, MD, a gastroenterologist at Digestive Healthcare of Georgia in Atlanta with clinical expertise in inflammatory bowel disease (IBD). “[Avoiding these foods can] help minimize the risk of flare-ups and manage symptoms effectively.”

Kadle also suggests avoiding:

  • Added sugars in cookies, pastries, or other sweets
  • High-sodium foods
  • Red and processed meats, such as beef, lamb, deli meat, or bacon
  • Alcohol 
  • Sugar sweetened beverages, such as soda, juice, or flavored coffee drinks with syrup
  • Spicy foods, such as sriracha or chili powder
  • Fatty foods, such as butter or fried foods
  • Carbonated drinks 
  • Coffee
  • Dairy products, such as cow’s milk, ice cream, or cream
  • Additives like cellulose gum (carboxymethylcellulose) or polysorbate-80

Is rice bad for Crohn’s disease?

Rice is not bad for Crohn’s. In fact, rice can be a better food choice — especially during a flare-up. Both white and brown rice can be part of a healthy diet. Brown rice is more nutrient-dense. It’s a better choice if you need more fiber, vitamins, and minerals.

But during a Crohn’s flare-up, your gut can be more sensitive. White rice is lower in fiber and might be easier for you to digest. Depending on how you feel, pick what works best for your system. 

Are eggs OK for Crohn’s?

Yes, eggs can also be a good choice with Crohn’s. Eggs can be an excellent source of protein, especially during flare-ups. Instead of cutting out certain foods, it’s better to focus on variety. 

Try mixing eggs in with other protein sources. You can eat eggs with chicken, fish, or tofu. This can help you meet your nutritional needs and keep your diet balanced.